Ultrasonically-sealable peelable seal

Abstract

A packaging material has a peelable seal and a sealing of resin which is ultrasonically-sealable, but not readily heat-sealable backed by a backing layer of resin having a higher melting point than the sealing layer. The interlayer adhesion between the backing layer and the sealing layer is below the strength required to break the sealing layer. The thickness and material of the sealing material is utilized to control the seal strength of the peelable end seal of the package.

What is claimed is: 
     
       1. A package seal which is ultrasonically-sealable and maintains a peelable seal feature, the peelable seal comprising: (a) a sealing layer of resin material which is ultrasonically-sealable, but is not readily heat-sealable,   (b) a backing layer for the sealing layer, the backing layer being of a higher melting point resin than the sealing layer, the interlayer adhesion between the backing layer and the sealing layer being below the strength required to break the sealing layer.   
     
     
       2. A peelable package seal as in claim 1 further comprising at least one outer laminating layer. 
     
     
       3. The peelable package seal of claim 2 wherein said outer layer is a laminated layer. 
     
     
       4. The peelable package seal of claim 2 wherein said outer layer is a printed layer. 
     
     
       5. The peelable package seal of claim 2 wherein said outer layer is a coextruded layer. 
     
     
       6. The peelable package seal of claim 1 or 2 wherein the sealing layer resin is selected from the group consisting of: ionomer resins, nylon, polybutylene, polyester, high density polyethylene, medium density polyethylene, low density polyethylene, copolymers of ethylene and one or more materials selected from the group consisting of propylene, vinyl acetate, ethyl acrylate, methyl acrylate, acrylic acid, and vinyl alcohol, polypropylene, and polystyrene. 
     
     
       7. The peelable package seal of claim 1 or 2 wherein the sealing layer resin is a polymer, said polymer being treated with slip agents, jaw release chemicals or processing aids. 
     
     
       8. The peelable package seal of claim 1 or 2 wherein the backing layer resin is selected from the group consisting of: polyacrylonitrile, nylon, polycarbonate, polyester, high density polyethylene, medium density polyethylene, copolymers of ethylene and one or more materials selected from the group consisting of propylene, vinyl acetate, ethyl acrylate, methyl acrylate, acrylic acid, and vinyl alcohol, polypropylene, polystyrene and polyvinylidene chloride. 
     
     
       9. The peelable packge seal of claim 6 wherein the backing layer resin is selected from the group consisting of: polyacrylonitrile, nylon, polycarbonate, polyester, high density polyethylene, medium density polyethylene, copolymers of ethylene and one or more materials selected from the group consisting of propylene, vinyl acetate, ethyl acrylate, methyl acrylate, acrylic acid, and vinyl alcohol, propylene, polystyrene and polyvinylidene chloride. 
     
     
       10. The peelable package seal of claims 1 or 2 wherein the outer layer comprises polypropylene, ink, and low density polyethylene; the backing layer comprises nylon; and the sealing layer comprises high density polyethylene. 
     
     
       11. The peelable package seal of claims 1 or 2 wherein the outer layer comprises lacquer, ink, kraft paper and adhesive; the backing layer comprises polyester; and the sealing layer comprises polypropylene. 
     
     
       12. The peelable package seal of claims 1 or 2 wherein the outer layer comprises lacquer, ink, ethylene vinyl acetate, white high density polyethylene, brown high density polyethylene, and a tie; the backing layer comprises nylon; and the sealing layer comprises high density polyethylene. 
     
     
       13. The peelable package seal of claims 1 or 2 wherein the outer layer comprises high density polyethylene and a first tie; the backing layer comprises nylon; the sealing layer comprises high density polyethylene; and a second tie is disposed between the backing layer and the sealing layer, said second tie controls the adhesion of the backing layer and the sealing layer. 
     
     
       14. The peelable package seal of claims 1 or 2 wherein the sealing layer peels off from the backing layer when a pulling force is applied to one end of the package seal. 
     
     
       15. The peelable package seal of claims 1 or 2 wherein the seal strength ranges from 100 grams per inch to 1,800 grams per inch. 
     
     
       16. A peelable package seal comprising film-type packaging material which is sealed by ultrasonic techniques. 
     
     
       17. A peelable package seal comprising an end seal which is sealed by ultrasonic techniques.